1. Field of the Invention
The invention relates to oilfield downhole operations. More particularly, the invention relates to a swage device for reforming a deformable junction in a deviated wellbore.
2. Prior Art
As is well known to those of skill in the art, reformable deformed junctions have been known to the oilfield art. The benefit of a deformed junction is that the junction is easily transported through the casing of a wellbore or an open hole wellbore to its final destination at a junction between a primary and lateral borehole. Once the junction is properly positioned, it is reformed into a Y-shaped junction to assist in completing the wellbore. In the fully reformed condition of the junction, the outer dimensions are generally greater than the inside diameter (ID) of the casing or open hole. Thus, of course, it would be rather difficult to install the junction in its undeformed condition. Many methods have been used to reform the deformed junction in the borehole. One of the prior art methods has been to employ a swaging device. Swaging devices generally comprise a conical or frustoconical hardened member having an outside diameter (OD) as large as possible while being passable through the wellbore casing or the open hole. This swage is forced to travel through a previously positioned deformed junction whereby the junction is reformed into an operational position. Where the junction is located in a vertical or near vertical wellbore, setdown weight alone often is sufficient to generate the approximately 100,000 pounds of force required to reform the junction. Where the deformed junction is being placed in a highly deviated wellbore or a horizontal wellbore, however, setdown weight might not be sufficient to force the swage device through the junction. In this event, one of skill in the art will recognize the hydraulic procedure alternative to setdown weight. This hydraulic procedure includes an expansion joint located above the swage device, a drill tube anchor located above the expansion joint, and a ball seat located below the expansion joint such that by dropping a ball, pressure can be applied to the tubing string. This applied pressure forces the expansion joint to expand downhole, which in turn forces the swage device through the junction. Expansion joints are well known in the art, as are anchors and ball seats.
As also will be recognized by one of ordinary skill in the art, there is a significant drawback to the prior art swaging devices. The metal of the junction has a certain amount of resilience such that after the swage device has been forced through the junction, reforming the same, the junction itself will rebound to a smaller ID than the OD of the swage device by several thousandths of an inch. Because of the rebound it requires nearly as much lifting force on the swage device to remove it from the wellbore as is needed to initially force the swage through the deformed junction. This can be as much as 100,000 pounds. Although a drilling rig can easily pull ten times this weight, in a highly deviated or horizontal wellbore, the friction created on the curvature of the well can be high enough to absorb all of the force imparted at the surface and leave none available for the swage. Thus, the tool is stuck. The amount of force necessary to pull the swage through the newly reformed junction can also be sufficient to damage other well tools or junctions. Such damage can of course cost significant sums of money to repair and require significant time both to diagnose and to repair. Thus, the art is in need of a swage device that does not carry the drawbacks of the prior art.
The above-identified drawbacks of the prior art are overcome or alleviated by the flexible swage device of the invention.
The invention avoids the above set forth drawback by creating a two-part swage device comprising a support and a swage cup. The support is engaged with the swage cup during the swaging operation. The swage cup is moveable such that after the swaging operation is complete, the swage cup can be moved to a position where it is unsupported by the support and is therefore allowed to deflect several thousandths of an inch toward the mandrel. This deflection will significantly reduce drag on the swage cup through the reformed junction (and any other junctions uphole of the subject junction) during removal of the swage device from the wellbore. In an alternate embodiment, the swage cup contains longitudinal slots cut into it to impart increased flexibility characteristics to the swage cup. The flexible swage device of the invention is employable in place of a conventional swage, the function of which being fully assimilated in the invention.